 Okay, so the next thing we're going to do today is just show the mechanism of this simple addition of HBr to ethylene. So we're doing a hydrobromination, so hopefully you see. Here we have this carbon, is that carbon which an H has been added to it. And this carbon here is this carbon which a bromine has been added to it. So we call this an addition action because this particular molecule here has been added to this molecule. So A and A plus B becomes C. So in order to show the mechanism we're going to have to erase some of this stuff and then explicitly draw out the bonds of HBr and then also show the lone pairs. So remember HBr is a strong acid. So if we want the hydrogen to go to this carbon here, remember the double bond is going to be the base. So show that first set of arrows like that. You'll be doing this reaction mechanism quite a bit. There will be some nuances to it when you get bigger structures, but this is effectively the mechanism for any time you see HBr being added to a double bond. So what did we do? We have two hydrogens there and we're adding the third one. We've got one, two, three hydrogens there. We haven't done anything to this carbon so we still got its two hydrogens there and it lost that electron there from the double bond so there's a positive charge. We call that a carbocation. This is an intermediate to this particular reaction. We also have Br minus that we formed in the initial step of the reaction. So recall the Br in the final product is attached to this carbon so there's one more step, the Lewis acid base mechanism. So we just take those electrons and attack that carbon there and we get our final product. So I know you all are writing right now and you probably have a bunch of questions but you don't know where to start asking them. So I'd like for you to get this mechanism in your head and start being able to do this and then maybe next time we can tackle some of your questions, okay? Unless you have any right now, does anybody have any first time you look at this? Okay, I'll kill it and then next time you can ask questions on this one.